Most disposable containers being widely used currently are ones formed by foaming and compression-molding synthetic resin such as polystyrene or the like, and ones formed by jetting synthetic resin on the surface of paper which is a primary material.
It is a trend that the use amount of disposable containers increases every year with more fast food consumed in food-related life style amongst our contemporaries. However, foamed polystyrene containers contain chemicals harmful to human bodies like producing environmental hormones and so on, and the problem of disposing of the used containers is growing more serious according to the increase of the use amount of the containers.
Accordingly, in recent, researches and developments are actively ongoing that replace the polystyrene with natural polymer materials which can be obtained from grain starch or wheat flour, grain skins, and so on. As examples using grain powder, there exists a method molding, freezing, and coating dough obtained from mixing wheat flour, starch, sodium bicarbonate, and salt (Republic of Korea Patent No. 96-0006565), a method aging, extruding, molding, and freeze-drying dough obtained from mixing purified water of proper temperature with grain starch and wheat flour as primary materials and sugar, spices, yeast, and so on supplementary materials(Republic of Korea Patent No.99-0047173), and the like. Further, as illustrations using grain skins, there exists a method mixing ground skins of rice, barley, foxtail millet, Indian millet and so on, water, and starch, molding, and then coating for rinal products(Republic of Korea Patent No. 99-0055567), and a method wherein plant particles as a basic material are obtained from grinding corn stalks or various grain skin, mixed with edible gelatin, compressed through a molder for final products(Republic of Korea Patent No. 99-0037967), and so on.
However, such products are so heavy, fragile, and shrunk due to ambient temperatures that lots of limitations are applied in use as primary materials in order to solve the problems, indecomposable additives are inevitably used in many occasion. Therefore, there still exists decomposability problems as well as difficulties in practical usage due to high prices.